In recent years, in the fields of automobiles, electronic products, industrial equipment and the like, there is an increasing trend where a portion of a metal molded article is replaced with a resin molded article in order to respond to the demands of reducing carbon dioxide emission, manufacturing costs and the like. In connection with this, composite molded articles are widely used in which resin molded articles are integrated with metal molded articles. Without limited to this, composite molded articles in which molded articles of similar or dissimilar materials are integrated together are also widely used.
Further, a resin material filled with an inorganic filler such as glass fiber is often used, and the orientation of the inorganic filler upon molding the material is often an issue. Therefore, various methods of observing an inorganic filler are used.
As a method of manufacturing a composite molded article in which one molded article is integrated with another molded article, the following have been proposed, for example. Patent Document 1 proposes a method comprising: mixing a filler such as glass fiber with one resin to perform molding; subjecting the other resin to chemical, plasma, flame treatments and the like to remove a resin with a thickness of one severalth of micrometers to tens of micrometers; and then performing filling and molding while the other resin is allowed to make contact with a surface for adhering the other resin, thereby achieving adhesion. Further, Patent Document 2 proposes a method comprising: irradiating a surface of one resin molded article with electromagnetic radiation to form a nano structure in the above surface; and then performing filling and molding while the other resin molded article is allowed to make contact with the above surface, thereby achieving integration
Further, the following are also commonly performed: a resin is observed after removing a surface resin of a resin molded article to expose an inorganic filler by cutting, grinding the surface, or treating the surface with a chemical and the like; and an inorganic filler inside a resin molded article is observed with an X-ray CT.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. H01-126339
Patent Document 2: Japanese Unexamined Patent Application (Translation of PCT Application), Publication No. 2011-529404